The overall objective of the proposed interdisciplinary research program is to develop a series of data bases on which assessment of potential health consequences, especially total burden of environmental carcinogens and mutagens resulting from combustion of fossil fuels can be made more objectively and with greater precision than is currently possible. The general approach is intended to define conditions of combustion for several fuel types, including readily vaporized fuel, coal, heavy oil and shale oil, which generate minimal amounts of compounds of carcinogenic and/or mutagenic properties. Several approaches will be utilized, involving the collaboration of combustion engineers, analytical chemists, and biologists. Lines of investigation to be pursued include: (1) Parametric studies will be conducted on small scale burners to determine effects of temperature, equivalence ratio and fuel type on the formation of organic and inorganic particulates; (2) Selected samples from the combustion experiments will be subjected to chemical analysis using GC-MS for soot extracts and size-fractionation, neutron-activation analysis and surface characterization for inorganic particulates; (3) Evaluations will be made of biological and biochemical properties of selected samples produced under defined combustion conditions with respect to: mutagenicity in bacteria and human cells; ability to form covalent adducts with nucleic acids when activated in vitro and in vivo; carcinogenecity in rats and ability to induce biochemical changes in lung tissue; and relative irritant potency as indicated by altered respiratory mechanics in guinea pigs; (4) Selected samples produced by combustors operated under conditions defined in small-scale burners and preliminary biological experiments will be characterized chemically and biologically; and (5) Utilizing data producted by the above experimental approaches, a data evaluation from emission to impact utilizing probabilistic simulations to assess health impacts from various source/control configurations will be conducted.